docs: new troubleshooting guide + cors fix (#6387)

- Fixed CORS middleware to account for routes of a single path (for example, `/custom` and not just `/custom/test`).
- Added a troubleshooting guide for admin webpack errors (see issue #6375)

www/apps/docs/content/development/api-routes/create.mdx

@@ -128,7 +128,7 @@ import cors from "cors"
 export const config: MiddlewaresConfig = {
   routes: [
     {
-      matcher: "/custom/*",
+      matcher: "/custom*",
       middlewares: [
         cors({
           origin: "*",

www/apps/docs/content/plugins/notifications/sendgrid.mdx

@@ -145,7 +145,7 @@ const plugins = [
       product_created_template: 
         process.env.SENDGRID_ORDER_CREATED_ID,
       my_custom_event_template:
-        process.env.SENDGRID_CUSTOM_EVENT_ID
+        process.env.SENDGRID_CUSTOM_EVENT_ID,
     },
   },
 ]

www/apps/docs/content/troubleshooting/admin-webpack-build-types.md

@@ -0,0 +1,91 @@
+---
+title: Admin Webpack Build Error
+---
+
+If you run the `build` command in your backend and you get an error message during the admin build process similar to the following:
+
+```bash
+The left-hand side of an assignment expression must be a variable or a property access.
+```
+
+Make sure that in your admin customizations (widget, UI route, or settings page) you're not using a type imported from `@medusajs/medusa`.
+
+This is often the case if you're using a type or an enum necessary for a request sent with the JS Client or Medusa React library.
+
+For example:
+
+```ts
+import { 
+  Region, 
+  ShippingOptionPriceType,
+} from "@medusajs/medusa"
+import type Medusa from "@medusajs/medusa-js"
+
+export default async function prepareShippingOptions(
+  client: Medusa, 
+  region: Region
+) {
+  let { 
+    shipping_options,
+  } = await client.admin.shippingOptions.list({
+    region_id: region.id,
+  })
+  if (!shipping_options.length) {
+    shipping_options = [(
+      await client.admin.shippingOptions.create({
+        "name": "PostFake Standard",
+        "region_id": region.id,
+        "provider_id": "manual",
+        "data": {
+          "id": "manual-fulfillment",
+        },
+        // THIS CAUSES THE ERROR
+        "price_type": ShippingOptionPriceType.FLAT_RATE,
+        "amount": 1000,
+      }
+    )).shipping_option]
+  }
+
+  return shipping_options
+}
+```
+
+In this case, you're using the `ShippingOptionPriceType` type to send a request with the JS Client.
+
+Instead, change it to the string value. If you get a TypeScript error, you can add `// @ts-ignore` before the line:
+
+```ts
+import { 
+  Region, 
+  ShippingOptionPriceType,
+} from "@medusajs/medusa"
+import type Medusa from "@medusajs/medusa-js"
+
+export default async function prepareShippingOptions(
+  client: Medusa, 
+  region: Region
+) {
+  let { 
+    shipping_options,
+  } = await client.admin.shippingOptions.list({
+    region_id: region.id,
+  })
+  if (!shipping_options.length) {
+    shipping_options = [(
+      await client.admin.shippingOptions.create({
+        "name": "PostFake Standard",
+        "region_id": region.id,
+        "provider_id": "manual",
+        "data": {
+          "id": "manual-fulfillment",
+        },
+        // @ts-expect-error can't use type from core
+        "price_type": "flat_rate",
+      "amount": 1000,
+      }
+    )).shipping_option]
+  }
+
+  return shipping_options
+}
+```

www/apps/docs/sidebars.js

@@ -2244,6 +2244,11 @@ module.exports = {
           id: "troubleshooting/custom-hooks-error",
           label: "Custom Hooks Error",
         },
+        {
+          type: "doc",
+          id: "troubleshooting/admin-webpack-build-types",
+          label: "Webpack Build Error",
+        },
       ],
     },
     {